diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7bc5983..289a62b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,7 @@ set(CPACK_SOURCE_INSTALLED_DIRECTORIES
     "${CMAKE_CURRENT_SOURCE_DIR}/eur_nkg/" "."
     "${CMAKE_CURRENT_SOURCE_DIR}/fr_ign/" "."
     "${CMAKE_CURRENT_SOURCE_DIR}/is_lmi/" "."
+    "${CMAKE_CURRENT_SOURCE_DIR}/nc_dittt/" "."
     "${CMAKE_CURRENT_SOURCE_DIR}/nl_nsgi/" "."
     "${CMAKE_CURRENT_SOURCE_DIR}/nz_linz/" "."
     "${CMAKE_CURRENT_SOURCE_DIR}/pt_dgt/" "."
diff --git a/agency.json b/agency.json
index 80bf6df..a9cae5e 100644
--- a/agency.json
+++ b/agency.json
@@ -95,6 +95,12 @@
         "agency":"National Land Survey of Iceland",
         "url": "https://atlas.lmi.is/LmiData/index.php?id=626468364600"
     },
+    {
+        "id": "nc_dittt",
+        "country": "New Caledonia",
+        "agency":"Gouvernement de Nouvelle Calédonie - DITTT",
+        "url": "https://dittt.gouv.nc/circe-pour-la-nouvelle-caledonie"
+    },
     {
         "id": "nl_nsgi",
         "country": "Netherlands",
diff --git a/copyright_and_licenses.csv b/copyright_and_licenses.csv
index 38cba73..6c5106d 100644
--- a/copyright_and_licenses.csv
+++ b/copyright_and_licenses.csv
@@ -137,6 +137,10 @@ is_lmi_ISN93_ISN2016.tif,"Copyright 2017-2019, National Land Survey of Iceland",
 is_lmi_ISN_vel_beta.tif,"Copyright 2017-2019, National Land Survey of Iceland",CC-BY-4.0
 is_lmi_README.txt,Disclaimed,Public domain
 NKG,Nordic Geodetic Commission,CC-BY-4.0
+nc_dittt_gr3dnc01b.tif,Gouvernement de Nouvelle Calédonie - DITTT,Open License France - https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf
+nc_dittt_gr3dnc02b.tif,Gouvernement de Nouvelle Calédonie - DITTT,Open License France - https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf
+nc_dittt_gr3dnc03a.tif,Gouvernement de Nouvelle Calédonie - DITTT,Open License France - https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf
+nc_dittt_README.txt,Disclaimed,Public domain
 nl_nsgi_naptrans2018.tif,Nederlandse Samenwerking Geodetische Infrastructuur (NSGI),CC-BY-4.0
 nl_nsgi_nlgeo2018.tif,Nederlandse Samenwerking Geodetische Infrastructuur (NSGI),CC-BY-4.0
 nl_nsgi_rdcorr2018.tif,Nederlandse Samenwerking Geodetische Infrastructuur (NSGI),CC-BY-4.0
diff --git a/grid_tools/convert_gr3dnc01b.py b/nc_dittt/convert_gr3dnc01b.py
similarity index 84%
rename from grid_tools/convert_gr3dnc01b.py
rename to nc_dittt/convert_gr3dnc01b.py
index b3ed17e..c169de0 100755
--- a/grid_tools/convert_gr3dnc01b.py
+++ b/nc_dittt/convert_gr3dnc01b.py
@@ -68,16 +68,33 @@
             ds = gdal.GetDriverByName('GTiff').Create(
                 '/vsimem/gr3dnc01b.tif', cols, rows, 3, gdal.GDT_Float32)
             ds.SetMetadataItem(
-                'TIFFTAG_COPYRIGHT', 'Derived from work by Service Topographique, DITTT, GNC. License unclear')
+                'TIFFTAG_COPYRIGHT', 'Derived from work by Service Topographique, DITTT, Government of New Caledonia. Open License https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf')
             ds.SetMetadataItem('TIFFTAG_IMAGEDESCRIPTION',
-                               'Geocentric translation from IGN72 GRANDE TERRE (EPSG:4662) to RGNC91-93 (EPSG:4749). Converted from gr3dnc01b.mnt')
+                               'Geocentric translation from IGN72 GRANDE TERRE (EPSG:4662) to RGNC91-93 (EPSG:4906). Converted from gr3dnc01b.mnt')
             datetime = datetime.date.today().strftime("%Y:%m:%d %H:%M:%S")
             ds.SetMetadataItem('TIFFTAG_DATETIME', datetime)
             ds.SetMetadataItem('AREA_OR_POINT', 'Point')
             ds.SetMetadataItem('TYPE', 'GEOCENTRIC_TRANSLATION')
-            ds.SetMetadataItem('area_of_use', 'France')
-            ds.SetMetadataItem('source_crs_code', '4662')
-            ds.SetMetadataItem('target_crs_epsg_code', '4749')
+            ds.SetMetadataItem('area_of_use', 'New Caledonia')
+            ds.SetMetadataItem('source_crs_wkt', """GEODCRS["IGN72 Grande Terre",
+    DATUM["IGN72 Grande Terre",
+        ELLIPSOID["International 1924",6378388,297,
+            LENGTHUNIT["metre",1]],
+        ID["EPSG",6634]],
+    PRIMEM["Greenwich",0,
+        ANGLEUNIT["degree",0.0174532925199433],
+        ID["EPSG",8901]],
+    CS[Cartesian,3],
+        AXIS["(X)",geocentricX,
+            ORDER[1],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Y)",geocentricY,
+            ORDER[2],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Z)",geocentricZ,
+            ORDER[3],
+            LENGTHUNIT["metre",1]]]""")
+            ds.SetMetadataItem('target_crs_epsg_code', '4906')
             ds.SetGeoTransform(
                 [minx - resx/2, resx, 0, maxy + resy/2, 0, -resy])
             ds.GetRasterBand(1).SetUnitType('metre')
diff --git a/nc_dittt/convert_gr3dnc02b.py b/nc_dittt/convert_gr3dnc02b.py
new file mode 100755
index 0000000..bb4ed13
--- /dev/null
+++ b/nc_dittt/convert_gr3dnc02b.py
@@ -0,0 +1,138 @@
+#!/usr/bin/env python
+###############################################################################
+# $Id$
+#
+#  Project:  PROJ
+#  Purpose:  Convert New Caledonia geocentric gr3dnc02b.mnt grid
+#  Author:   Even Rouault <even.rouault at spatialys.com>
+#
+###############################################################################
+#  Copyright (c) 2019, Even Rouault <even.rouault at spatialys.com>
+#
+#  Permission is hereby granted, free of charge, to any person obtaining a
+#  copy of this software and associated documentation files (the "Software"),
+#  to deal in the Software without restriction, including without limitation
+#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
+#  and/or sell copies of the Software, and to permit persons to whom the
+#  Software is furnished to do so, subject to the following conditions:
+#
+#  The above copyright notice and this permission notice shall be included
+#  in all copies or substantial portions of the Software.
+#
+#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+#  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#  DEALINGS IN THE SOFTWARE.
+###############################################################################
+
+from osgeo import gdal
+from osgeo import osr
+import datetime
+import struct
+
+with open('gr3dnc02b.mnt', 'rt') as f:
+    count_val_rows = 0
+    line_no = 0
+    for l in f.readlines():
+        if l[-1] == '\n':
+            l = l[0:-1]
+        if l[-1] == '\r':
+            l = l[0:-1]
+        if not l:
+            continue
+        if line_no == 0:
+            tokens = []
+            for t in l.split(' '):
+                if t:
+                    tokens.append(t)
+            assert len(tokens) >= 13
+            minx = float(tokens[0])
+            maxx = float(tokens[1])
+            miny = float(tokens[2])
+            maxy = float(tokens[3])
+            resx = float(tokens[4])
+            resy = float(tokens[5])
+            assert minx < maxx
+            assert miny < maxy
+            assert resx > 0
+            assert resy > 0
+            cols = 1 + (maxx - minx) / resx
+            assert cols - int(cols + 0.5) < 1e-10
+            cols = int(cols + 0.5)
+            rows = 1 + (maxy - miny) / resy
+            assert rows - int(rows + 0.5) < 1e-10
+            rows = int(rows + 0.5)
+            ds = gdal.GetDriverByName('GTiff').Create(
+                '/vsimem/gr3dnc02b.tif', cols, rows, 3, gdal.GDT_Float32)
+            ds.SetMetadataItem(
+                'TIFFTAG_COPYRIGHT', 'Derived from work by Service Topographique, DITTT, Government of New Caledonia. Open License https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf')
+            ds.SetMetadataItem('TIFFTAG_IMAGEDESCRIPTION',
+                               'Geocentric translation from IGN72 GRANDE TERRE (EPSG:4662) to RGNC91-93 (EPSG:4906). Converted from gr3dnc01b.mnt')
+            datetime = datetime.date.today().strftime("%Y:%m:%d %H:%M:%S")
+            ds.SetMetadataItem('TIFFTAG_DATETIME', datetime)
+            ds.SetMetadataItem('AREA_OR_POINT', 'Point')
+            ds.SetMetadataItem('TYPE', 'GEOCENTRIC_TRANSLATION')
+            ds.SetMetadataItem('area_of_use', 'New Caledonia')
+            ds.SetMetadataItem('source_crs_wkt', """GEODCRS["IGN72 Grande Terre",
+    DATUM["IGN72 Grande Terre",
+        ELLIPSOID["International 1924",6378388,297,
+            LENGTHUNIT["metre",1]],
+        ID["EPSG",6634]],
+    PRIMEM["Greenwich",0,
+        ANGLEUNIT["degree",0.0174532925199433],
+        ID["EPSG",8901]],
+    CS[Cartesian,3],
+        AXIS["(X)",geocentricX,
+            ORDER[1],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Y)",geocentricY,
+            ORDER[2],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Z)",geocentricZ,
+            ORDER[3],
+            LENGTHUNIT["metre",1]]]""")
+            ds.SetMetadataItem('target_crs_epsg_code', '4906')
+            ds.SetGeoTransform(
+                [minx - resx/2, resx, 0, maxy + resy/2, 0, -resy])
+            ds.GetRasterBand(1).SetUnitType('metre')
+            ds.GetRasterBand(1).SetDescription('x_translation')
+            ds.GetRasterBand(2).SetUnitType('metre')
+            ds.GetRasterBand(2).SetDescription('y_translation')
+            ds.GetRasterBand(3).SetUnitType('metre')
+            ds.GetRasterBand(3).SetDescription('z_translation')
+            sr = osr.SpatialReference()
+            sr.ImportFromEPSG(4749)
+            ds.SetProjection(sr.ExportToWkt())
+        else:
+            tokens = []
+            for t in l.split('\t'):
+                if t:
+                    tokens.append(t)
+            assert len(tokens) == 6
+            lon = float(tokens[0])
+            lat = float(tokens[1])
+            dx = float(tokens[2])
+            dy = float(tokens[3])
+            dz = float(tokens[4])
+            iy = (line_no - 1) % rows
+            ix = (line_no - 1) // rows
+            assert abs(lon - (minx + ix * resx)
+                       ) < 1e-10, (line_no, lon, minx + ix * resx)
+            assert abs(lat - (miny + iy * resy)
+                       ) < 1e-10, (line_no, lat, miny + iy * resy)
+            ds.GetRasterBand(1).WriteRaster(
+                ix, rows - iy - 1, 1, 1, struct.pack('f', dx))
+            ds.GetRasterBand(2).WriteRaster(
+                ix, rows - iy - 1, 1, 1, struct.pack('f', dy))
+            ds.GetRasterBand(3).WriteRaster(
+                ix, rows - iy - 1, 1, 1, struct.pack('f', dz))
+            count_val_rows += 1
+
+        line_no += 1
+
+    assert count_val_rows == rows * cols
+    gdal.GetDriverByName('GTiff').CreateCopy('gr3dnc02b.tif', ds, options=[
+        'COMPRESS=DEFLATE', 'PREDICTOR=3', 'INTERLEAVE=BAND'])
diff --git a/grid_tools/convert_gr3dnc03a.py b/nc_dittt/convert_gr3dnc03a.py
similarity index 84%
rename from grid_tools/convert_gr3dnc03a.py
rename to nc_dittt/convert_gr3dnc03a.py
index 85c35a3..c8db270 100755
--- a/grid_tools/convert_gr3dnc03a.py
+++ b/nc_dittt/convert_gr3dnc03a.py
@@ -68,16 +68,33 @@
             ds = gdal.GetDriverByName('GTiff').Create(
                 '/vsimem/gr3dnc03a.tif', cols, rows, 3, gdal.GDT_Float32)
             ds.SetMetadataItem(
-                'TIFFTAG_COPYRIGHT', 'Derived from work by Service Topographique, DITTT, GNC. License unclear')
+                'TIFFTAG_COPYRIGHT', 'Derived from work by Service Topographique, DITTT, Government of New Caledonia. Open License https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf')
             ds.SetMetadataItem('TIFFTAG_IMAGEDESCRIPTION',
-                               'Geocentric translation from NEA74 Noumea (EPSG:4644) to RGNC91-93 (EPSG:4749). Converted from gr3dnc03a.mnt')
+                               'Geocentric translation from NEA74 Noumea (EPSG:4644) to RGNC91-93 (EPSG:4906). Converted from gr3dnc03a.mnt')
             datetime = datetime.date.today().strftime("%Y:%m:%d %H:%M:%S")
             ds.SetMetadataItem('TIFFTAG_DATETIME', datetime)
             ds.SetMetadataItem('AREA_OR_POINT', 'Point')
             ds.SetMetadataItem('TYPE', 'GEOCENTRIC_TRANSLATION')
-            ds.SetMetadataItem('area_of_use', 'France')
-            ds.SetMetadataItem('source_crs_code', '4644')
-            ds.SetMetadataItem('target_crs_epsg_code', '4749')
+            ds.SetMetadataItem('area_of_use', 'New Caledonia')
+            ds.SetMetadataItem('source_crs_wkt', """GEODCRS["NEA74 Noumea",
+    DATUM["NEA74 Noumea",
+        ELLIPSOID["International 1924",6378388,297,
+            LENGTHUNIT["metre",1]],
+        ID["EPSG",6644]],
+    PRIMEM["Greenwich",0,
+        ANGLEUNIT["degree",0.0174532925199433],
+        ID["EPSG",8901]],
+    CS[Cartesian,3],
+        AXIS["(X)",geocentricX,
+            ORDER[1],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Y)",geocentricY,
+            ORDER[2],
+            LENGTHUNIT["metre",1]],
+        AXIS["(Z)",geocentricZ,
+            ORDER[3],
+            LENGTHUNIT["metre",1]]]""")
+            ds.SetMetadataItem('target_crs_epsg_code', '4906')
             ds.SetGeoTransform(
                 [minx - resx/2, resx, 0, maxy + resy/2, 0, -resy])
             ds.GetRasterBand(1).SetUnitType('metre')
diff --git a/nc_dittt/nc_dittt_README.txt b/nc_dittt/nc_dittt_README.txt
new file mode 100644
index 0000000..e3a0809
--- /dev/null
+++ b/nc_dittt/nc_dittt_README.txt
@@ -0,0 +1,33 @@
+# nc_dittt_README.txt
+
+The files in this section result from the conversion of datasets originating
+from [Gouvernement de la Nouvelle-Calédonie – DITTT](https://dittt.gouv.nc/circe-pour-la-nouvelle-caledonie)
+
+## Included grids
+
+### New Caledonia: IGN72 GRANDE TERRE (EPSG:4662) to RGNC91-93 (EPSG:4906) (using Geocentric correction)
+
+*Source*: Gouvernement de la Nouvelle-Calédonie – DITTT](https://dittt.gouv.nc/circe-pour-la-nouvelle-caledonie)  
+*Format*: GeoTIFF converted from .mnt file with convert_gr3dnc01b.py  
+*License*: [License Ouverte (in French)](https://www.etalab.gouv.fr/wp-content/uploads/2017/04/ETALAB-Licence-Ouverte-v2.0.pdf) / [Open License (English translation)](https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf)
+*Used by*: [EPSG:9329 Transformation](https://www.epsg-registry.org/export.htm?gml=urn:ogc:def:coordinateOperation:EPSG::9329)
+
+* nc_dittt_gr3dnc01b.tif
+
+### New Caledonia - Noumea: IGN72 GRANDE TERRE (EPSG:4662) to RGNC91-93 (EPSG:4906) (using Geocentric correction)
+
+*Source*: Gouvernement de la Nouvelle-Calédonie – DITTT](https://dittt.gouv.nc/circe-pour-la-nouvelle-caledonie)  
+*Format*: GeoTIFF converted from .mnt file with convert_gr3dnc02b.py  
+*License*: [License Ouverte (in French)](https://www.etalab.gouv.fr/wp-content/uploads/2017/04/ETALAB-Licence-Ouverte-v2.0.pdf) / [Open License (English translation)](https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf)
+*Used by*: [EPSG:9330 Transformation](https://www.epsg-registry.org/export.htm?gml=urn:ogc:def:coordinateOperation:EPSG::9330)
+
+* nc_dittt_gr3dnc02b.tif
+
+### New Caledonia - Noumea: NEA74 Noumea (EPSG:4644) to RGNC91-93 (EPSG:4906) (using Geocentric correction)
+
+*Source*: Gouvernement de la Nouvelle-Calédonie – DITTT](https://dittt.gouv.nc/circe-pour-la-nouvelle-caledonie)  
+*Format*: GeoTIFF converted from .mnt file with convert_gr3dnc03a.py  
+*License*: [License Ouverte (in French)](https://www.etalab.gouv.fr/wp-content/uploads/2017/04/ETALAB-Licence-Ouverte-v2.0.pdf) / [Open License (English translation)](https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf)
+*Used by*: [EPSG:9328 Transformation](https://www.epsg-registry.org/export.htm?gml=urn:ogc:def:coordinateOperation:EPSG::9328)
+
+* nc_dittt_gr3dnc03a.tif
diff --git a/nc_dittt/nc_dittt_gr3dnc01b.tif b/nc_dittt/nc_dittt_gr3dnc01b.tif
new file mode 100644
index 0000000..ca8c779
Binary files /dev/null and b/nc_dittt/nc_dittt_gr3dnc01b.tif differ
diff --git a/nc_dittt/nc_dittt_gr3dnc02b.tif b/nc_dittt/nc_dittt_gr3dnc02b.tif
new file mode 100644
index 0000000..96c2c89
Binary files /dev/null and b/nc_dittt/nc_dittt_gr3dnc02b.tif differ
diff --git a/nc_dittt/nc_dittt_gr3dnc03a.tif b/nc_dittt/nc_dittt_gr3dnc03a.tif
new file mode 100644
index 0000000..786da45
Binary files /dev/null and b/nc_dittt/nc_dittt_gr3dnc03a.tif differ
diff --git a/travis/expected_main.lst b/travis/expected_main.lst
index 801849b..5a39017 100644
--- a/travis/expected_main.lst
+++ b/travis/expected_main.lst
@@ -136,6 +136,10 @@ is_lmi_ISN2004_ISN2016.tif
 is_lmi_ISN93_ISN2016.tif
 is_lmi_ISN_vel_beta.tif
 is_lmi_README.txt
+nc_dittt_gr3dnc01b.tif
+nc_dittt_gr3dnc02b.tif
+nc_dittt_gr3dnc03a.tif
+nc_dittt_README.txt
 NKG
 nl_nsgi_naptrans2018.tif
 nl_nsgi_nlgeo2018.tif